When the race started, everyone was all smiley.

Then after a mile or so, everyone stopped smiling.

After five miles, everyone had on their marathon faces: pain, misery and anguish.

And on we ran. And on. And on.

I felt so sorry for the people in costumes. You could tell they were really suffering – especially the ones with Father Christmas beards and padding.

It was so much harder than in training.

And SO cold. My lungs were absolutely burning and my fingers were bright red.

The crowd do cheer you on and cheer you up. But marathons are still horrible and gruelling and only professional athletes or maniacs should attempt them, let alone in winter.

By the time we crossed Tower Bridge, every step was agony.

All I could think was, ‘I want to stop, I want to stop!’

I wasn’t thinking about pacing myself or anything, just running and running.

At the halfway mark, I saw Mum, Dad, Laura, Brandi and Althea.

Dad was waving a Union Jack flag.

Mum was eating a mince pie. She went mental when she saw me.

‘WOOOOOOOOOOO JULES! WOOOOOOOOO JULIETTE! COME ON GIRL! SHOW THEM WHAT YOU’RE MADE OF, DO YOU WANT A PORK PIE?’

My eyes welled up when I saw Daisy.

Mum had put pink leg warmers and baby trainers over her snow suit.

Dad was all manic-eyed. ‘Are you enjoying it? It’s amazing isn’t it? What the human body can do.’

He was still in his shorts and vest, jogging on the spot and blowing on his fingers.

I told him it was the worst thing I’d ever done in my life. I said my body wasn’t made for running, but gentle walking and massages. I said I would never, ever run another marathon as long as I lived and made him promise not to let me do it again.

Mum said, ‘Only thirteen miles to go.’

Dad said. ‘Thirteen and a half!’

Laura told me to think of Daisy and how proud she’d be.

‘She doesn’t care,’ I said. ‘She doesn’t have the slightest clue what’s going on.’

‘Then do it for you,’ said Laura.

‘I don’t care about me either!’ I said. ‘I just want to stop. This is awful. AWFUL! There is no way I can finish. No way.’

Laura put a calming sisterly hand on my shoulder and said, ‘You can do it.’

I said, ‘I think I might sit down and have a bit of pork pie …’

Laura said, ‘No. You have to keep going.’

I started crying and said I couldn’t do it. I said my chest hurt. And my ears hurt. And my boobs hurt. And I kept seeing people on stretchers who’d slipped on the ice.